Electric burglar-alarm.



Patented Nov. :4,- I899.

G. MGGANN.

ELECTRIC BURGLAR ALARM.

(Appiication filed Mar. 21, 1898.)

(No Modal.) 2 Sheeis$heet 'ea. .77? fail/m:- I

N0. 637,0!2. Patented Nov. l4, I899.

I 1 G. MBGANN.

ELECTRIC BURGLAR ALARM.

(Application filed Mar. 21, 1898.) M m 2 Sheets'-Sheat 2.

Y NORRIS PETERS ca, PuoYoLrrHo" WASmNGTQN o a f w Wf m UNITED STATES PATENT OFFICE.

GEORGE MOGANN, OF ST. LOUIS, MISSOURI, ASSIGNOR TO THE COMMERCIAL TELEGRAPH COMPANY, OF SAME PLACE.

ELECTRIC BURGLAR-ALARM.

SPECIFICATION refuting but of Letters Patent Nb. 637,012, dated November 14, 1899 Application filed March 21,1898. Serial No. 674,602. (No model.)

To all whom it may concern:

Be it known that I, GEORGE MOGANN, of the city of St. Louis, State of Missouri, have invented certain new and useful Improvements in Electric Burglar-Alarms, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part hereof.

My invention relates generally to electric burglar-alarms, and more particularly to that class of burglar-alarms in which the entrance of an unauthorized person into a building provided with my improved alarm will operate an audible and visible signal at the central office. I

The principal object of my invention is to locate means in the protection-circuit-that is, the circuit in the protected buildingand also means in the central office which will operate the signal whenever unauthorized persons attempt an entrance to a building in which the protection-circuit is located,which means is also made use of in testing the circuit-that is, to ascertain positively at any time whether or not the protection-circuit is in proper working order. I

My invention consists of the novel construction, combination, and arrangement of parts hereinafter shown, described, and claimed.

Figure 1 represents in diagram an electric burglar-alarm circuit embodying my improvements. Fig. 2 is a plan view of a polarized relay constructed in accordance with my invention. Fig. 3 is a cross-sectional view taken approximately on the line 3 3 of Fig. 2. Fig. 4 is a bottom view of this polarized relay and shows the connections therein.

Referring by numerals to the accompanyin g drawings,1-indicates the building in which the central station is located, and 2 the building equipped with the protection-circuit. The magnets 3 and 4 of a balanced relay are located in the central oftice 1, the magnet 3 being connected to one end of the conductor 5, the opposite end of which is connected to a push-plug 6, the end of which carries a horizontally-arranged contact-pin 7. This contact-pin 7 is normally in contact with the point of a contact-spring 8, from which leads a conductor 9, that is connected to a battery being identical with the push-plug 6.

10, the opposite pole of said battery being grounded by the conductor 11. A contactspring 12 is'provided with a conductor 13, that leads to a battery 14, which is of the 5 5 same strength as, but of opposite polarity, to the battery 10, which last-mentioned battery 14 is grounded by the wire 15.

The magnets 3 and 4 of the balanced relay are properly connected, and the conductor 16, leading from the magnet 4, is connected to a contact-spring 17, the point of which is normally engaged by a contact-pin 18, carried by the free end of the push-plug 19, the same To the push-plug 19 is connected one end of the line 20, that leads to the protection-circuit in the protected building or buildings.

A contact-spring 21, opposite the contactspring 17, is provided with a point to be engaged by the contact-pin 18, and to said contact-spring 21 is connected the end of a conductor 22, that leads to a relay 23. A conductor 24 from the magnet of said relay leads to a battery 25, said battery being grounded by the conductor 26.

The armature 27 of the magnet-coil 3 is provided on its end with a contact-point 28, which is normally held out of engagement with the I point of a contact-screw 29, suitably located, 'to which contact-screw is connected one end of a conductor 30, that leads to a battery 31. The armature 32 is provided on its end with a contact-point, which is normally held against the contact-screw 33, for the reason that the energization of the magnet 4 attracts the armature 32 and overcomes the resistance of a small coil-spring 34, that is so arranged as to pull the armature 32 away from the magnet and the contact-screw 33 when the magnet 4 0 is not energized. Leading from the armature 27 to the armature 32 is aconductor 35, connected to armature 32. Leading from the contact-screw 33 to the conductor 30 is a conductor 36. One end of aconductor 37 is con- 5 nected to the armature 32 and leads from thence to a magnet-coil 38,there being a switch 39 located in said conductor 37. To this coil I 38 is connected one end of a conductor 40, that leads from the battery 31, previously I00 mentioned. 'The energization of the magnet 38 operates a bell-crank lever 41, which in turn operates a drop 42, there being a conductor 43 leading from one end of said drop to one binding-post of a bell 44. This drop 42 is so arranged that when it falls it will make a contact with the plate 45, said plate being connected to one end of a conductor 46, that leads to the opposite binding-post of the bell 44, there being a battery 47 located in said conductor 46. The mechanism and connections just described are very similar to systems now in use, with the exception of the first push-plug 6 and connections thereto.

Located in the protected building are the magnet-coils 48 and 49 of a polarized relay, the armature 50 of which is provided with a section 51, of insulating material, in its end. A contact-point 52 projects laterally from the metallic end of this armature 50, and upon the outer face of the section of insulating material is located a metallic plate 53, from which projects a contact-point.

A non-conducting arm 54 is pivoted at one end so that its free end is in juxtaposition to the block of insulating material 51, and said free end of the arm 54 carries a contactpin 55, the point of which is normallyin contact with the contact-point of the plate 53. Carried by the arm 54 is a leaf-spring 56, the outer end of which engages against the point of an adjusting-screw 57. A retractile coilspring 58, suitably located, normally draws the contact-pin 55 into engagement with the contact-point of the plate 53. The point of a contact-screw 59 is in alinement with and adapted to be engaged by the contact-point 52.

Located on the doors, windows, and other places of entrance to the building in which the protection-circuit is located are the usual contact plugs and springs 60, which are all properly connected in the line-wire 20, the end of said wire being led to a magnet 49 of the polarized relay. A conductor 61 leads from the opposite magnet 48 to the adjusting-screw 57, and leading from the spring 56, that is normally in contact with said adjusting-screw 57, is a conductor 62, that leads to a resistance-coil 63. Leading from said resistance-coil is a conductor 64, that is properly connected with the contact-plugs which are located on the doors and windows, and said conductor 64 is finally grounded. This conductor 64 is connected to the armature 50 by means of the conductor 64. Leading from the contact-screw 59 to the conductor 62 is a conductor 65. Located in the central oflice is a battery 66, and leading from one pole of said battery to the plate 53, carried by the block of insulating material 51, is a conductor 67. Leading from the opposite pole of this battery to the contact-pin 55, carried by the arm 54, is a conductor 68, in which conductor is located a relay 69 of the ordinary construction, which relay is also located in the circuit 70 of the local battery 71, there being a register 72 or other-suitable recordinginstrument located in said circuit 70.

As the action of the major portion of the alarm system herein shown and described is well known to the users of such alarms, I do not deem it necessary to trace all of the circuits or describe the actions of the various parts, so will confine myself to the action and operation of my improvements to the system.

Normally the circuit through the balanced relay and through the protection-circuit is as follows: from the ground, through the conductor 11 to the battery 10, through the conductor 9 to the contact-spring 8, from thence through the contact-pin 7, through the pushplug 6, through the conductor 5 to the magnet-coil 3, from thence to the opposite magnet 4, through the conductor 16 to the contact-spring 17, the contact-pin 18, and pushplug 19 to the line conductor 20, from thence through the contact-springs 60 of the devices located upon the doors and windows, through the conductor 20 to the magnet 49, from thence to the magnet 48, through the conductor 61, adjusting-screw 57, contact-spring 56, conductor 62, resistance-coil 63, and, finally, through the conductor 64 to the ground. Whenever the operator at the central ofiice wishes to test the protection-circuit to see that the polarized relay is in operative condition and that the circuit is complete, the push-plug 19 is pushed in until the contact-pin 18 contacts with the point of the contact-spring 21. This action cuts in the relay 23, the circuit being from the ground through the conductor 26 to the battery 25, through the conductor 24 to the relay 23, through the conductor 22 to the contact-sprin g 21, through the contact-pin 18, push-plug19, to theline conductor20, from thence to the coil 49, the coil 48, conductor 61, adjusting-screw 57, the contact-spring 56, conductor 62, resistance-coil 63, and, finally, through the conductor 64 to the ground. As the current through the thus-established circuit is greatly increased owing to the cutting in of the battery 25, which battery is of the same polarityas, but of much greater strength than, the battery 10, the magnets 48 and 49 will be energized to move the armature 50 toward the contact-pin carried by the arm 54. The pressure of the armature 50 against this arm 54 will cause the contact-spring 56 to leave the pointof the adjusting-screw 57, thus breaking the circuit. As soon as the circuit breaks, the coil-spring 58 will pull the arm 54 toward the armature 50, and thus establish the circuit through the spring 56 and adjusting-screw 57. Thus a vibratory action is established, each vibration being reproduced upon the relay 23, and thus an audible vibratory signal assures the operator in the central station that the protection-circuit is in perfect operative condition.

It is possible in a burglar-alarm system of the class described that a burglar or unauthorized person seeking entrance to the building in which the protection-circuit is located is supplied with instruments that could be tapped or located in the protection-circuit, so as to sound the vibrations of the relay 23, and

IIO

to overcome such a possibility a short-circuit test is made use of, which test is as follows: The push-plug 6 is pushed in until the contact-pin 7 thereof is in contact with the point of the contact-spring 12. This spring 12 is connected to the battery 14, which battery is, as heretofore stated, of the same strength as, but of opposite polarity to, the battery 10, and circuit will then be established as follows: from the ground through the conductor 15 to the battery 14, through the conductor 13 to the spring 12, contact-pin 7, push-plug 6, conductor 5, coil 3, coil 4, conductor 16, spring 17, pin 18, push-plug 19, line conductor 20, contacts 60, coil 49, coil 48, conductor 61, ad-

justing-screw 57, contact-spring 56, conductor 62, resistance-coil 63, and, finally, through the conductor 64 to the ground. This circuit thus established, it will be noted, is almost the same as the normal circuit; but as the battery 14, Which is of the same strength as, but of opposite polarity to, the battery 10, is substituted a dilferent act-ion of the armature 5O will result, which action is to move laterally until the contact-point 52 engages against the point of the adjusting-screw 59. The circuit now will be from the conductor 62 through the conductor 65, screw 59, contact-point 52, armature 50, conductor 64 to the conductor 64, which is grounded. Thus the resistancecoil 63 will be cut out, and by thus lowering the resistance the strength of the coil 3 will be increased sufficiently to pullthe armature 28 toward the contact-point 29,and thus thelocal signal-circuit in which the drop 42 and bell 44 are located will be completed and said drop will fall and the bell tvillring, thus completing the short-circuit test. course constitutes a visible signal. In addition to this short-circuit test, the armature 50 at the same time breaks the contact between the contact-point 53 and contact-pin 55, carried by the arm 54, which opens the call-circuit, and thus makes an additional test and safeguard. These signals will be repeated as often as the push-plug 6 is pushed in. This short circuit test enables the operator in the central station to adjust the relay 3 so that it will respond to the cutting out of the resistance-coil 63, and with such proper adj ustment the relay 3 will be absolutely certain to operate and will respond to the opening of any door or window in the protection-circuit. If when the operator adjusts the relay 3 in the central station to correspond with the cutting out of the resistance in the protection-circuit the signals are not given, he will know that the protection-circuit has been Said drop of tampered with in some way or other by unauthorized persons.

.Thus it will be seen how I have provided an electric burglar-alarm with means whereby the protection-circuits in said alarm may be tested to ascertain to an absolute certainty whether said lines have been tampered with and whether or not they are in perfect operative condition.

I claim 1. In aburglar-alarm system, a protectioncircuit, a polarized relay having an armature provided with a section of insulating material in its end, contact-points secured to the metallic end of the armature and to the insulating material, a resistance-coil located in the protection-circuit adjacent the polarized relay, a balanced relay located in the central station and connected with the protection-circuit, a relay 23 comprising an audible signal and connected with the balanced relay, and a pushplug whereby the operation of the said pushplug synchronously operates the polarized relay, balanced relay and said audible signal, substantially as specified.

2. In a burglar-alarm system, a protectioncircuit, a polarized relay, a spring-actuated arm, the end portions of which are insulated, a contact-spring fixed to the insulated part of said arm, a contact-pin passing through the insulated free end of said arm, a resistance-coil located in the protection-circuit adjacent the polarized relay, a balanced relay located in the central station and connected with the protection-circuit, visible and audible signals connected with the balanced relay, and a push-plug whereby the operation of said push-plug synchronously cuts-out the resistance and operates the balanced relay and the signals, substantially as specified.

3. The improved polarized relay for a burglar-alarm system, comprising the combination with the relay-armature, of a block of insulating material located in the end of said armature, suitable contacts in said insulating material and in the end of said armature, a spring-actuated arm having insulated ends, a leaf-spring carried by the uninsulated portion of said arm,a con tact-pin passing through the insulated free end of said arm, suitable circuit connections, and contacts 55, 57 and 59, substantially as specified.

In testimony whereof I affix my signature in presence of two witnesses.

GEORGE MOGANN. Witnesses:

A. J. MOOAULEY, M. P. SMITH. 

